Sapling number 17

[Natallie K 3B]

How can you determine whether a molecule is color or not before learning about the shape? For example, what is the reason that BF3 is non polar and NF3 is polar. Does it have to do with the lone pair? Sapling explains it in terms of molecular shape, but since we have not covered that yet, I was wondering if there is another explanation.

[Joseph Hsing 2C]

Yes, you're right, electron repulsion from the lone pair pushes the other fluorine bonds which contribute to molecular shape which in turn makes an overall molecule polar or nonpolar. Hope this helped.

[Aliya 1H]

Yeah, the lone pair in NF3 makes it so that the fluorines are pushed away and thus changes the molecular shape as well so that it is polar/no longer symmetrical. The BF3 has no lone pairs and has a symmetrical shape/is non-polar.

[Janna Shakiba]

If you would like me to show you my work for Sapling hw problem #17, email me!

[Nathan Chu 3H]

For the example you provided, BF3 is non polar because the polarity/dipole of the 3 B-F bonds all cancel out each other. In the NF3 molecule, the lone pair does not allow this to happen and thus the molecule will overall have a charge and be polar.